"To send a confidential note to Cyrus the Great along heavily guarded roads, sixth-century-BC Median noble Harpagus inserted a paper message into a dead hare’s belly and ordered a servant to pose as a hunter to deliver the corpse."

"Even a paranoid can have enemies." -Henry Kissinger, 1977

"Walter Kirke, British deputy head of military intelligence in France, noted in his diary in October 1915 that the chief (“C”) of the Secret Intelligence Service had come upon a solution for how to send secret messages: “Heard from C that the best invisible ink is semen,” Kirke wrote. The substance, it turned out, was hard to detect by the common revealing method of iodine vapor. The chief’s name: Mansfield Cumming."